Okay, so most of these jokes should have been left in 2014 where we buried them. As for the rest, uh, there aren't any. Unless all caps, swearing, and "SKELEBALLS" count as jokes, but we're all 15+ here so they really shouldn't.

I think you just didn't get the joke. See, it's a skeleton, and then it says "skeleballs", which is "balls" but with "skele" on the front as in "skeleton", thereby referencing testicles and rendering the entire article humorous. If that's not humor, I don't know what is.

So, as much as I kind of hate doing this kind of thing, I went out and did a little reading of my own, and that is the only link I've seen that says anything even remotely like that, with everything else being along the lines of "A douchebag" or "Dickish player" type definition.

But, that article itself even points out that it didn't originate in the prison system, stemmed from that song (I guess?), and was only later (supposedly) reclaimed as a prison term. This article is the only source I could find, so I can't really say how accurate any of that even is. The word isn't even included in the "prison lingo" page linked from that very article.

2) Do not, not ever, believe any singular source that claims something is offensive because of an etymological fallacy, and do not, not ever, inform others of in a "Now that you know this fact, do what I say" kind of fashion if you've acquired this knowledge yourself from such a false source.

(This is your reminder that the word "bad" comes from the word "baeddel")